U.S. Pat. No. 4,754,247 entitled "Molded Case Circuit Breaker Accessory Enclosure" describes a circuit breaker and accessory which are mainly assembled together in an automated manufacturing process. The circuit breaker rating plug and the accessory units are down-loaded within recesses formed in the circuit breaker cover during assembly with little or no manual intervention. A manually accessible trip test button is generally provided on the top surface of the circuit breaker cover to allow an operator to trip the circuit breaker operating mechanism to determine whether the circuit breaker mechanism is functional. There are several existing trip test button designs that rely upon the depression of the trip test button or the rotation thereof to effect internal contact with the circuit breaker operating mechanism.
One example of a two-piece circuit breaker "twist-to-trip" trip test button is found in U.S. Pat. No. 3,671,890 entitled "Manually Operable Molded Case Circuit Breaker With Special Trip Testing Means". The trip test button described therein is formed from two separate injection molded plastic pieces. The top piece consists of an externally accessible cylindrical trip test button positioned within a recess formed in the circuit breaker cover. A bottom piece includes a pair of angled legs wherein one of the legs interacts with the circuit breaker trip bar while the other leg resiliently interacts with a stop on the circuit breaker cover to return the trip test button to its original position. This Patent is incorporated herein for purposes of reference and should be reviewed for its teaching of the interaction of an externally accessible trip test button with the internal circuit breaker trip bar and operating mechanism.
One example of a "slide-to-trip" trip test button is found in U.S. Pat. No. 4,740,768 entitled "Manual Trip Operator for Molded Case Circuit Breaker" which Patent is incorporated herein for reference purposes. This Patent describes a single plastic trip operator that is down-loaded within the circuit breaker cover in a single automated assembly process and utilizes the resilience of the plastic material to return the trip operator to its initial position.
In some applications, a "push-to-trip" trip test button is required such as with a self-trip industrial-rated circuit breaker whereby the circuit breaker automatically becomes tripped by interaction between a trip projection formed on the associated circuit breaker enclosure and the trip test button on the circuit breaker when the circuit breaker is withdrawn from the enclosure.
One purpose of the instant invention, accordingly, is to provide a "push-to-trip" trip test button assembly unit that is assembled within a circuit breaker cover in an automated assembly process and is capable of self-trip function when utilized within a supplemental circuit breaker enclosure.